Presentation on theme: "Recent Seismicity in the Mozambique Region by T T Molea and L Akromah (Council for Geoscience: Seismology Unit) Seisan workshop October 2008 Norway."— Presentation transcript:
Recent Seismicity in the Mozambique Region by T T Molea and L Akromah (Council for Geoscience: Seismology Unit) Seisan workshop October 2008 Norway
OUTLINE The East African Rift System as a source of tectonics Seismicity of southern Africa 1620 - 2007 Mozambique earthquake of 22/02/2006 Conclusion
The East African Rift System
Seismicity of southern Africa (1620 – 2007)
609 Recording Stations
Location & Magnitude –USGS :7.4 –CTBTO: 6.4 –CGS :7.2. –Epicentre : Machaze, in the ( Manica Province of Mozambique) –Recording Time –22:19:05.8. –This is believed to be the largest instrumentally recorded earthquake in Mozambique.
Epicentre by USGS
Damage & Intensity Maximum vertical displacement; ± 2m. Maximum horizontal displacement; ± 60km. Shaking was strong enough to kill 4 people and injured at least 29 more. Felt by people throughout Mozambique as well as in parts of the neighbouring countries of South Africa,Swaziland, Zambia, Zimbabwe.
Seismological Action Taken – Location by: USGS, CTBTO & CGS. – Moment Tensor by Harvard University – Source of earthquake mechanism investigated by Fenton & Bommer of Imperial College London. – Field survey by the DNG ( geological survey) of Mozambique.
Conclusion This was the largest instrumentally recorded seismic event in Mozambique. The event was felt over a wide area, thus leading to the suspicion that the attenuation in southern Africa is lower than previously thought. The earthquake occurred on a previously unknown lineament which begs the question whether other capable geologic features may be present in the area.
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Seismic pattern of Southern Africa –Tectonics movement of fault plates in the East Africa Rift Valley. –Rift consist of 2 main lines : E & W branch. –W.branch starts in Lake Albert - DRC through Lake Malawi & terminate in S. Mozambique. –E. branch extends from triple junction between, Arabian,Nubian & Somalian plates in the North to Southern Tanzania. –A third south-eastern branch continue through the Mozambique channel.